The presence of deleterious or undesirable material such as potentially pathogenic material such as viruses and/or bacteria in biological fluid is of great concern during many protocols, particularly those involving the processing of blood and/or blood components, e.g., to prepare transfusion products to be administered to a patient. For example, the introduction of disease causing material such as microorganisms, viruses and/or endotoxins into a patient, e.g., through administration of a contaminated fluid, may have serious, and possibly fatal, ramifications for the patient.
Additionally, those who handle the contaminated fluid and/or care for the patient may also face health risks resulting from exposure to the pathogens. Furthermore, the presence of microorganisms and/or viruses may adversely affect cell cultures and/or pose a health threat to laboratory technicians who handle the contaminated fluid or the fluid processing equipment.
Accordingly, a variety of protocols have been proposed to kill and/or inactivate potentially pathogenic material in biological fluid. Some protocols for inactivating microorganisms such as viruses and/or bacteria include exposing the material to light (or other forms of radiation), in the presence of an inactivating agent such as psoralen or methylene blue. It is believed that these inactivating agents are photoactive, so that in the presence of light they will react with the membrane structures and/or nucleic acids of the material in such a manner that the material, e.g., viruses and/or bacteria, may be killed, or prevented from replicating. With respect to reacting with the nucleic acids, it is believed that the photoactive agent cross-links to and/or damages the nucleic acids. It is also believed that some photoactive agents cause the conversion of molecular oxygen to oxygen radicals which are highly reactive and may have virucidal effects.
In some countries, some of these inactivating agents have been approved as licensed products that may be administered to a patient. Accordingly, material (e.g., blood or a blood component) treated with an inactivating agent may be administered to the patient without removing the agent. Apparently, since some regulations allow the administration of an inactivating agent to a patient, the art has not generally addressed the removal or separation of the agent from the material to be administered.
However, while some regulations may expressly allow the administration of an inactivating agent, this agent is "foreign" to the recipient's system, and it would be preferable to remove it before administering the material to a patient. Additionally, since inactivating agents are thought to bind to and/or damage nucleic acids, i.e., DNA and RNA, and damage to nucleic acids could lead to mutations, and possibly disease and/or birth defects, it would be desirable to minimize a patient's exposure to agents that could bind and/or damage nucleic acids.
There are other protocols that involve the removal or depletion of deleterious or undesirable material from biological fluids that could be beneficially combined with a protocol for inactivating and/or killing material such as viruses and/or bacteria. For example, since blood and blood components may include varying numbers of white blood cells (leukocytes), which may cause undesirable effects when administered to a patient, blood processing techniques may also include leukocyte depleting the blood or blood components, e.g., by passing the blood or blood components through a leukocyte depletion device. Since blood may also include potentially pathogenic material such as bacteria and/or viruses, it would be advantageous to provide a killing and/or inactivation procedure that is compatible with a leukocyte depletion protocol.
The present invention provides for ameliorating at least some of the disadvantages of the prior art protocols for treating blood. These improvements, and other advantages of the present invention, will be apparent from the description as set forth below.